Two-cycle internal combustion engine



June 26, 1934. c. e. cuR'rls ET AL 1,964,036

TWO-CYCLE INTERNAL COMBUSTION ENGINE I Filed July 5, 1929 2 Sheets-Sheet 1 I I firzz J6-- J4, 1 J4 June 26, 1934. c. G. CURTIS ET AL 1,

IWO-CYCLE INTERNAL COMBUSTION ENGINE Filed July 5, 1929 2 Sheets-Sheet 2 Retented June 26, 1934 TWO-CYCLE INTERNAL COMBUSTION ENGINE Charles G. Curtis, New York, and Earle R. Newton, Jamaica, N. Y., assignors to Curtis Gas Engine Corporation, New York, N. Y., a corporation of New York Application July 5, 1929, Serial No. 375,928. In Great Britain and Germany October 18,

2 Claims. (01. 123-61) This invention relates to double acting internal combustion engines and provides improvements therein.

The present invention may be embodied in a double acting two-cycle engine such as patented by us Nov. 4,1930, Number 1,730,175.

The novel feature of this invention is the combination of a set of inlet ports, serving both ends of a double-acting cylinder alternately and comprising ports oblique to the longitudinal axis of the cylinder, arranged when uncovered to direct air in one direction lengthwise of the cylinder, with a double acting piston and rod, which at one end of the piston stroke act as a deflector opposite direction.

An embodiment of the invention is illustrated in the accompanying drawings; wherein Figs. 1

and 2 are vertical sectional views of said embodiment, with the piston shown at the top and bottom respectively of its stroke, Figs. 3, 4 and 5 are vertical sectional views in the port locality, the sections being at diiierent angles, passing through themiddle port, an adjacent port and an end port respectively.

Fig. 6 is a horizontal section through the portsection.

Referring to said drawings, numeral 10 designates a cylinder of a two-cycle internal combustion engine; numeral 12 a reciprocating double acting piston; numeral 14 a bank of inlet ports located in the'cylinder wall in a position to be opened and closed by the piston; and numeral 16 a bank of exhaust ports also located in the cylinder wall on the opposite side in position to be opened and closed by the piston 12.

The bank of inlet ports 14 may be in communlcation, as illustrated in 6, with the usual air belt 18. The exhaust ports 16 may also be connected with the usual exhaust belt 20, as

illustrated in said figure.

Referring to Fig. 6, the bank of inlet ports 14, comprises a number of individual ports 30, 30*, 31, 31 32, 32 33, 33*, 34. A greater or less numher of these ports may be used. One or more ports in the middle section of the bank, here shown as the port 34, is angled vertically. For example, it has an angle of 60 to the horizontal, and is arranged more or less radially. The port 34, shown in Fig. 6 is shown in vertical section in Fig. 3.

Ports adjacent to the middle port, as for ex ample the ports 33, 33*, in Figs. 4 and 6, are shown as directingtheir air streams inside of the cylinder center (see Fig. 6), and may be less to turn saidair stream to cause it to flow in an These ports 30 et seq. are illustrated in vertical section in Fig. 5.

By arranging the middle port or ports 34 vertically oblique, that is oblique to the longitudinal axis of the cylinder, the tendency of the air streams from these ports to cross the cylinder is '70 lessened and a better union of these streams with the streams coming from the more nearly horizontal end ports is obtained.

The vertically oblique ports (34, 33) in the,

middle portion of the bank will when scavenging a the top or outer end of the cylinder 10 be directing their air streams toward the outer cylinder cover, butwhen scavenging the bottom or inner end, that is the piston rod end. of the cylinder 10 these vertically oblique ports will be directing air streams against the piston. We have found by test that the piston rod end of the cylinder scavenges ahnost as efliciently with the middle ports directed toward the piston as if the middle ports were directed downward: that is," toward the inner cylinder cover, and also almost as efflcientlyas the upper end-due to the presence of the piston and rod which serve to turn and direct the air stream back toward the bottom or inner cylinder cover.

Although the combined eihciency of the top and bottom ends is not quite as high as if separate sets oi. ports were used, with the upper set pointing upward and the lower set pointing downward, the advantages of the above-described arrangement in reducing overall cylinder We illustrate a double-acting engine involving a single set of inlet ports for scavenging both ends of the double acting cylinder which gives high scavenging efficiency. Such an arrangement is important in the two-cycle engine art, because high scavenging efliciency is vital, and because the use of a single set of inlet ports for scavenging is desirable from a structural standpoint and also from the standpoint of maintaining a short engine cylinder.

Moreover, the invention permits of high scavenging efflciency when using pistons with flat or concave heads. From a combustion standpoint, especially with solid injection of fuel, non-convex; that is, flat or concave piston heads are preferable to convex heads or heads carrying projections, and therefore a scavenging arrangement permitting of the use of such heads and giving a very high scavenging efliciency is important. To secure high scavenging efi iciency, the combustion chamber must not be injured, and vice versa. This invention secures maximum scavenging efliciency with a desirable combustion chamber and a short double acting cylinder. 4

The general operation is the same as in well known two-cycle engines, and need not here be described. 1

When the middle ports are to serve as supercharging ports, they must of course be longer than the exhaust ports, as described in our Patent #1,'780,175 already referred to.

The invention may receive other embodiments than that herein specifically illustrated and described.

What is claimed is:

1. A two-cycle internal combustion engine comprising a double acting cylinder and pistonwith rod, said cylinder having a cover at each end, a single set of air inlet ports arranged in a bank on one side of the cylinder-wall supplying both the inner and outer ends of the cylinder alternately, the ports in the middle section of the bank arranged vertically obliquely in one direction so that the air streams are directed toward the cylinder cover when supplying one end of the cylinder and toward the piston in front of the rod when supplying the other end, and end ports of the bank more nearly horizontal and arranged to direct their air streams back toward the side of the cylinder-wall in which the inlet ports are located.

2. A two-cycle internal combustion engine, comprising a double acting cylinder and piston with rod, said cylinder having acover at each end, a single set of air inlet ports arranged in a bank on one side of the cylinder-wall supplying both the inner and outer ends of the cylinder alternately, the ports in. the middle section of the bank arranged vertically obliquely in one direction so that the air streams are directed toward the cylinder cover when supplying one end of the cylinder and toward the piston in front of the rod when supplying the other end, the ports adjacent the middle ports pointing less obliquely toward the, cylinder cover than the middle ports, and end ports of the bank more nearly horizontal and arranged to direct their air streams back toward the side of the cylinder wall in which the inlet ports are located.

CHARLES G. CURTIS EARLE R. NEWTON. 

